Process for preparing crystalline forms of 4,4&#39;-bis[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)-amino]-stilbene-2,2&#39;-disulfonic acid

ABSTRACT

Novel crystalline 4,4&#39;&#39;-bis((4-anilino-6-morpholino-1,3,5triazin-2-yl)-amino)-stilbene-2,2&#39;&#39; -disulfonic acid is provided by a procedure involving treating cyanuric chloride with 4,4&#39;&#39;diaminostilbene-2,2&#39;&#39;-disulfonic acid, reacting the product thus obtained, without isolation, with aniline followed by reacting the resulting product, without isolation, with morpholine and precipitating the product thus obtained by treatment with an acid. The new crystalline 4,4&#39;&#39;-bis((4-anilino-6-morpholino-1,3,5triazin-2-yl)-amino)-stilbene-2,2&#39;&#39; -disulfonic acid is incorporated in detergents, soaps or other laundry products and imparts to the aforesaid and similar materials, unexpected and surprising superior over-all performance properties.

United States Patent Tscharner et a1.

[ 51 Feb. 13,1973

PROCESS FOR PREPARING CRYSTALLINE FORMS OF 4,4 '-BIS[(4-ANILINO-6-MORPHOLINO-l,3,5- TRIAZIN-2-YL)-AMINO]-STILBENE-2,2'-DISULFONIC ACID Inventors: Christopher Tscharner, Neumattenweg 9,Benken-Baselland, Switzerland; Maurice Schwarz, 1 5 Appletree Lane;Richard Pichler, l l Westfield Rd., both of Warwick, RI. 02888 Filed:April 13, 1970 Appl. No.: 27,587

US. Cl. ..260/240.l, 252/110, 252/117,

252/524, 252/542, 26 /240 B Int. Cl. ..C07d 55/22 Field of Search..260/240 B, 240.1

References Cited UNITED STATES PATENTS Wilson .r; ..260/247.1 Obayashiet a1. ..252/152 Gold et a1 ..260/240 Tscharner ..260/240 FOREIGNPATENTS OR APPLICATIONS 1,485,673 5/1967 France ..260/240 1,093,50712/1967 Great Britain ..260/240 Primary Examiner1-Ienry R. JilesAssistant ExaminerG. Thomas Todd Att0rneyKarl F. Jorda and Martin J.Spellman [5 7 ABSTRACT The new crystalline4,4-bis[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)-amino]-stilbene-2,2'-disulfonic acid is incorporatedin detergents, soaps or other laundry products and imparts to theaforesaid and similar materials, unexpected and surprising superiorover-all performance properties.

3 Claims, 3 Drawing Figures PATENTEDFEB] 3191a SHEET 2 [IF 3 I N VENTOR.

PROCESS FOR PREPARING CRYSTALLINE FORMS OF 4,4'-BIS[(4-ANILINO-6-MORPHOLINO- l ,3 ,5-TRIAZIN-2-YL)-AMINO]-STILBENE-2,2DISULFONIC ACID DESCRIPTION OF THE PRIOR ART The use ofN,N-bis-triazinyl derivatives of 4,4- diaminostilbene-2,2-disulfonicacid for the brightening of cellulose and polyamide substrates has beenknown for a considerable period of time and has been greatly extendedfor use in the fluorescent whitening of textile materials. Thefluorescent whitening is effected today not only by the textile produceror finisher including the manufacturers of synthetic materials but, toan increasing extent, also by the housewife who washes her laundry withdetergents and/or soaps containing fluorescent whitening materials.Thus, in order to improve and/or increase the whitening effect,fluorescent whitening agents are incorporated into a washing agentduring the production of such agents.

In an attempt to impart to laundry (white loads) a whiter aspect, theproducers of washing agents have constantly increased the amount offluorescent whitener incorporated in their products. However, the use ofrelatively large concentrations of whitener, that is about 2-10 kgs. ofwhiteners per ton of detergent, often causes a distinct discoloration ofthe washing powder and this undesirable discoloration often increaseswhen the washing agent that is, the detergents, soaps or otherlaundering products are stored in a damp or humid atmosphere. Thefreedom from discoloration of the washing powder itself during theseveral stages of manufacture is used by the producer as a check andcontrol as the production steps are proceeding as desired. However, sucha manufacturing control is difficult or impossible if the mixturecontaining the fluorescent whitening agent actually causes discolorationof the product during its manufacture.

Canadian Pat. No. 783,566 relates to a salt of 4,4-bis(4-anilin0-6-morpholino-s-triazin-Z-ylamino)-2,2'- stilbenedisulfonicacid and more particularly, to a novel crystalline form of the disodiumsalt of the aforesaid acid. The aforesaid novel crystalline material ischaracterized by improved properties as an optical bleaching agent.

The disodium salt that is, disodium 4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate is aknown compound having valuable properties as a fluorescent opticalbleaching agent and which is used as a whitening and brightening agentin detergent compositions for laundering textile goods. However, theaforesaid known compound has been found to be objectionable because ofits light sensitivity and this light sensitivity is objectionableespecially when the product is incorporated into white detergents.

According to the procedure described in Canadian Pat. No. 783,566,disodium 4,4- bis (4-anilino-6- morpholino-s-triazin-2-ylamino )-2 ,2'-stilbenedisulfonate is obtained in the form of cream coloredneedleshaped crystals and such crystals are characterized by excellentlight stability. The novel procedure for preparing the aforesaid newcrystalline material involves heating, at a temperature between aboutand 200 C, amorphous disodium 4,4'-bis(4-anilinomorpholino-s-triazin-Z-ylamino)-2,2-stilbenedisulfonate withone-half to five molecular proportions of aniline or morpholine in anaqueous medium having an initial pH of about 8 to 12 until approximately80 to percent of the disodium 4,4'-bis(4-anilino-6--morpholino-s-triazin-2-ylamino)-2,2-stilbenedisulfonate is in the formof crystalline needles. However, the novel crystalline material is alsocharacterized by a series objectionable feature that is, itsunsuitability for use in detergent or laundering compositions, at lowtemperatures.

Further, the whitening effect of practically all fluorescent whiteningagents is substantially reduced at low temperatures. In addition, lowtemperature whitening agents yield yellow speckles in detergent onrecycling the detergent through the spray tower.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates tonew crystalline forms of 4,4'-bis[(4-anilino-6-morpholino-l,3,5-triazin-2-yl)-aminol-stilbene-2,g disulfonic m acid, cmmoNnossz, havingthe following chemical structural formula;

A He E I E www The new crystalline material possesses unusual and mostsurprising properties. Specifically, as indicated above, while theeffectiveness of most fluorescent whitening agents is substantiallyreduced at low temperatures, the fluorescent whitening effect at lowtemperatures of the novel crystalline forms of 4,4-bis-[(4-anilino-o-morpholino-l ,3,5-triazin-2-yl)-amino]-stilbene-2,2'-disulfonic acid are substantiallyunaffected. In addition to the aforesaid unusual property of extremelyhigh whitening effect at temperature, the novel crystalline material ofthe present invention is characterized by excellent bleach stability.Still further, while most fluorescent whitening agents used at lowtemperatures are troubled with the formation of yellow speckles, thenovel crystalline material of the present invention does not yieldyellow speckles. Thus, the novel crystalline forms of4,4'-bis[(4-anilino-6- morpholino-l ,3,5-triazin-2-yl)-amino]-stilbene-2,2 disulfonic acid possess the rareand most unusual combination of properties namely (1) detergent powderwhitener, (2) excellent fluorescent whitening effects even when used atlow temperatures, (3) excellent bleach stability and (4) freedom fromformation of yellow speckles.

The present invention also includes within its scope the use of theaforesaid fluorescent whitening agent in detergents, soaps and otherlaundry products such as bleaches, softeners, and the like.

disulfonic acid disodium salt product is recovered, by conventionalprocedures and suitably, by filtration. The product is then washed,acidified to a pH between about 2 and 6 and preferably between about 2and 3. The reaction involving the acidification of the disodium salt isillustrated as follows:

The starting materials used in preparing the novel product of thepresent invention are produced by known methods similar to thosedescribed, for example, in U.S. Pat. No. 2,762,801 or Swiss Pat. No.321,109. The procedure involves condensing 1 mol of disodium4,4'diaminostilbene-2,2-disulfonate or alternatively, the free acid thatis, 4,4'-diaminostilbene- 2,2'-disulfonic acid (DAS) with 2 mols ofcyanuric chloride (CC) at a low temperature that is, at a temperaturebetween about -l0 and C and preferably, between about 6 to +5C. Asuitable solvent and illustratively, methylethylketone, for cyanuricchloride is used in this step. The resulting intermediate product,disodium 4,4-bis(4,6- dichloro-s-triazin-2ylamino)-2,2'-stilbenedisulfonate (CC/DAS) is then reacted withaniline (2 mol equivalent to 1 mol of DAS) at a temperature betweenabout 5 and 50C and this step is followed by converting the remaining 2chlorines in the4,4'-bis-{2"-phenylamino-4"-chloro-striazinyl-(6")-amino1-stilbene-2,2'-disulfonicacid by heating the reaction mixture at a temperature between about 50and 90C with morpholine. The above steps in the process are performedcontinuously that is, without isolating the intermediate products. Thenovel step in the process involves acidifying the reaction mixture toobtain the desired product, i.e., 4,4'-bis[(4- anilino-fi-morpholino-l,3 ,5-triazin-2-yl )-amino 1 stilbene-2,2 '-disulfonic acid.

The new crystalline forms of 4,4'-bis[(4-anilino-6- morpholino-l ,3,5triazin-2-yl)-amino]-stilbene-2,2 disulfonic acid are obtained either,as indicated above, by acidifying the reaction mixture to a pH rangingbetween about 2 and 6 and preferably, between about 2 and 3 oralternatively, following the reaction with morpholine, the resulting4,4-bis[(4-anilino-6- morpholino-l ,3 ,5-triazin-2-yl)-amino1-stilbene-2,2

On acidification, the desired product precipitates our of solution andsaid product is then recovered by conventional means such as, forexample, by filtration. On drying, the desired product is obtained inthe form of a crystalline material.

The novel crystaliine products of the present invention provideoutstanding superior performance characteristics as compared with knownfluorescent whitening agents since, the present compound provides therare combination of unusually excellent detergent whitening abilitycoupled with excellent low temperature performance. ln addition to thisunusual combination, the present novel crystalline material does notform yellow speckels in detergents on recycling the latter through thespray tower and further, the products of the present invention are alsocharacterized by excellent bleach stability.

Still further, the crystalline material of the present invention iscapable of going into solution at an extremely rapid rate and thereforecan be drawn on to fibers at low temperatures that is, at temperaturesbetween about 35 and 60 C. Since the present product is available toexhaust on to the fabric even at low temperatures, its effectiveness atcold water washing is essentially equivalent to that of warm waterwashing. Consequently, the present product is ideally suitable for usein household laundering.

Solid detergents, including soaps and the like laundering compositions,to which the fluorescent whitening agents, according to the presentinvention, can be added at any step of their production include anionicdetergents such as alkali metal salts of alkyl-aryl sulfonatesespecially alkyl-benzene and alkyl-naphthalene sulfonates, alkali metalsalts of sulfates of higher fatty alcohol or alkali metal salts ofhigher fatty acids, in which the cation portion consists preponderantlyof sodium ions. The following is a typical anionic detergentformulation:

16% sodium dodecylbenzene sulfonate 35% sodium tripolyphosphate 5%tetrasodium pyrophosphate 6% sodium silicate 5% water 0.5%carboxymethylcellulose Balance to 100 percent sodium sulfate (exclusiveof additives) The present fluorescent whitener agent can also beincluded in nonionic detergent formulations and a typical formulation ofthis type is as follows:

8% nonylphenol polyethyleneglycolether 35% sodium tripolyphosphate 5%tetrasodium pyrophosphate 6% sodium silicate 8% water 0.5%carboxymethylcellulose Balance to 100% sodium sulfate (exclusive ofadditives) The amount of fluorescent whitener agent added is usually atleast about 0.1 percent up to about 1.0 by weight of the detergent,soap, softener, or like material.

The invention is illustrated in greater detail by the following exampleswhich are not considered to be limiting in any way. Unless otherwisestated, parts are given as parts by weight and the temperatures are indegrees Centigrade.

EXAMPLE 1 Preparation of 4,4-bis[ (4-anilino-6-morpholino-l,3,5-triazin-2-yl)-amino]-stilbene-2,2-disulfonic acid 100 parts of4,4'-bis[4-anilino-6-morpholino-l,3,5-triazin-2-yl)-amino]-stilbene-2,2'-disulfonic acid disodium salt and4,000 parts of water are heated, accompanied by agitation, at 80C. 260parts of 1.8 normal solution of hydrochloric acid in water is added in astream to achieve a pH of 2.5. The mixture is then tiltered, while hot,and the precipitate is washed with 2,000 parts of hot water. The wetmaterial is then dried at 100C, in vacuum, to obtain the desiredproduct, in crystalline form.

The crystalline product of this example is characterized by an X-raydiffraction diagram having the following characteristic lines expressedin 2 9:

Fairly strong lines at 5.3, 8.9, 11.4, 15.5, 19.8, 21.2

and 25.8

The X-ray pattern for this crystalline material is shown in accompanyingFIG. 1.

EXAMPLE I1 400 parts of water are heated, accompanied by agitation, at atemperature of 80C. To this solution is added a solution of parts of4,4-bis-[(4-anilino-6- morpholino-1,3,5-triazin-2-yl)-amino]-stilbene-2,2'- disulfonic acid disodium saltdissolved in 400 parts of water; Concurrently, a 1.0 normal solution ofhydrochloric acid in water is added at such a rate that the pH of theresultant solution is maintained at 6. After the addition of thebrightener solution,the temperature is kept at 80C and the pH ismaintained at 6 for an additional hour. The reaction mixture is thencooled to room temperature and filtered. The precipitate is washed withcold water to remove the salt and then dried at 100C in vacuum to obtainthe desired crystalline product.

The crystalline product is characterized by an X-ray diffraction diagramhaving the following characteristic lines expressed in 2 0:

A strong line at 9.3; a fairly strong line at 10.1; a strong line at16.3; fairly strong lines at 18.8, 19.3, 20.0, 23.3 and 24.6; a strongline at 25.5 and a fairly strong line at 28.1.

The X-ray pattern of this crystalline material is shown in accompanyingFIG. 3.

EXAMPLE Ill The procedure set out in Example 11 is followed except forthe fact that the pH was'maintained at 2 rather than at 6.

The crystalline product is characterized by an X-ray diffraction diagramhaving the following characteristic lines expressed in 2 0:

Fairly strong lines at 3.4 and 5.1; a strong line at 8.9 and fairlystrong lines at 9.7, 10.6, 15.9, 16.6, 18.5, 20.4, 21.5, 22.6 and 25.4.

The X-ray pattern of this crystalline material is shown in accompanyingFIG. 2.

EXAMPLE IV 700 Parts by weight of cyanuric chloride are added to 6,000parts by weight of methylethylketone and 6,000 parts by weight oficewater. A solution of 785 parts by weight of the sodium salt of4,4'-diaminostilbene-2,2-disulfonic acid and 200 parts by weight ofsodium carbonate in 6,000 parts by weight of water is poured, within 1hour, accompanied by stirring, at a temperature of 0.5C into thecyanuric chloride suspension thus obtained. 353 parts by weight ofaniline are added all at once and then the pH is held at 6-8 by theaddition of 155 parts by weight of sodium hydroxide dissolved in 155parts by weight of water. The yellowish suspension is then stirred andheated to 50C until all the aniline has disappeared. 665 Parts by weightof morpholine are added and the reaction is heated, accompanied byagitation, to distill the methethylketone at a temperature of about100C. The reaction mixture is allowed to cool to -90C and held at thistemperature while 300 parts by weight of sulfuric acid (98 percent) areadded, to a pH of 2-3 accompanied by agitation, within the one hour. Theyellow slurry is cooled and the solid material is recovered byfiltration. The wet product is dried at 100C in vacuum to obtain thedesired product, 4,4'-bis[(4- anilino-6-morpholino-l ,3 ,5-triazin-2-yl)-amino ]-stilbene-2,2'-disulfonic acid.

The crystalline product is characterized by an X-ray diffraction diagramidentical with the product of Example 1 supra.

The detergent whitening characteristics of this product were examined.The procedure used involved incorporating measured concentrations of theaforesaid whitener product into a typical anionic heavy duty detergentillustrated above by slurrying the detergent and whitener with about 1NNaOH until a smooth, homogeneous paste is obtained. The paste is driedin a gravity convection oven at C and the resulting dried detergent cakeis ground through a 20 mesh screen. The powder is sieved through a 60mesh screen and the fines are discarded. The detergent powder is thenallowed to stand overnight at about 85 percent relative humidity beforecolor measurement. The hue of the powder is measured on a Hunter ColorDifference Meter, Model D-25, using L", a, and b units. A whiteness"value is calculated according to the equation W=L+3a-3b (see Stensby,P.S., Soap and Chemical Specialties, April, May, July, August,September, 1967) the higher the value, the greater the whiteness of thepowder. Only whitener values above 75 can be considered measurement ofwhite.

All wash tests are carried out in a Terg-OTometer (150 rpm) for 10minutes using 600 ml water, 20 g cotton fabric, and l g detergent(containing 0.4 percent full strength whitener) predissolved for 30seconds prior to addition of fabrics or bleach. In tests with bleach,the wash liquor is exposed to 200 ppm NaOCl prior to addition of thefabrics. The washed fabrics are rinsed under running tap water anddrip-dried in the dark. Fabric fluorescence is measured using a LumetronColorimeter equipped with a mercury lamp and reflectance attachment, andfabric color is measured using the Hunter Color Difference Meter.

The performance characteristics of the product of Example 1V above werecompared with a low temperature whitener material which is presentlymarketed.

*A commercially available whitener, 4,4'-bis[4-ani1ino-6[bis(2-hydroxyethyD-amino1-l,3,5-triazin-2-yl]-amino-stilbene-2,2 '-disulfonicacid.

SPECKLING As compared with other low temperature whiteners some of whichare presently being sold, the crystalline material of Example 1V doesnot cause yellow speckling of detergent upon recycle of the detergent inspray drying operations.

Further, as indicated above, the novel crystalline material of thepresent invention is superior to the dis- 8 odium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2-stilbenedisulfonate disclosed in Canadian Pat. No. 783,566in that the last mentioned compound is unsuitable for use as a whiteningagent in detergent or laundering compositions at low temperatures. Thecomparison data set out above clearly indicates the superiority of thecrystalline material of the present invention both in detergentwhitening, high and low temperature performance as well as bleachstability.

The X-ray patterns of the crystalline material referred to above wereobtained by the well known pAowder technique described for instance, byKrug and lexander m -ray Diffraction Procedures for Polycrystalline andAmorphous Materials," published by John Wiley and Sons, New York, N.Y.(1954), especially on pages 235 et seq., using a Proportional- Counterequipped Goniometer made by N.V. Philips Gloeilampen Fabrieken,Eindhoven, Netherlands. The instrument does actually record theintensity of the diffracted ray along the vertical axis in relation tothe diffraction angle 26 using CuK radiation. The interplanar spacings dare subsequently calculated in Angstrom units from the diffractionangles by using the Bragg equation n. )t =2d. sin 0. The values givenare accurate within 2 percent and in most cases, particularly with dvalues of less than 10 A, variation is less than 1 percent. Therefore,this variation should be taken into account when interpreting thespecification and appendant claims.

What is claimed is:

1. In a process for the preparation of a crystalline form of4,4-bis[(4-anilino-6-morpholinol ,3,5-triazin-2-yl)-amino]-stilbene-2,2-disulfonic acid by a procedure involvingreacting cyanuric chloride with 4,4'-diaminostilbene-2,2'-disulfonicacid or an alkali metal salt thereof, contacting the CCIDAS product withaniline followed by contacting the product thus formed with morpholine,the improvement comprising acidifying the resulting4,4'-bis[(4-anilino-6- morpholinol,3,5-triazin-2-yl)-amino]-stilbene-2,2 disulfonic acid disodium salt,with a strong mineral acid at temperatures of from about 70-90C to a pHbetween 2 and 3 and purifying said acidulated product while at elevatedtemperatures.

2. The process in accordance with claim 1 including the steps ofconducting the acidulation of said disodium salt at a pH of about 6 andthereafter cooling said acidulation mix to ambient temperatures andthereafter purifying said disulfonic acid product.

3. The process in accordance with claim 2 including the step ofacidulating said salt at a pH of about 2.

t I I I It

1. In a process for the preparation of a crystalline form of 4,4''-bis((4-anilino-6-morpholino-1,3,5-triazin-2-yl)-amino)-stilbene-2,2''-disulfonic acid by a procedure involving reacting cyanurIc chloridewith 4,4''-diaminostilbene-2,2''-disulfonic acid or an alkali metal saltthereof, contacting the CC/DAS product with aniline followed bycontacting the product thus formed with morpholine, the improvementcomprising acidifying the resulting4,4''-bis((4-anilino-6-morpholino-1,3,5-triazin-2-yl)-amino)-stilbene-2,2''-disulfonic acid disodium salt, with a strong mineral acid attemperatures of from about 70*-90*C to a pH between 2 and 3 andpurifying said acidulated product while at elevated temperatures.
 2. Theprocess in accordance with claim 1 including the steps of conducting theacidulation of said disodium salt at a pH of about 6 and thereaftercooling said acidulation mix to ambient temperatures and thereafterpurifying said disulfonic acid product.